[SOLVED] FFmpeg libxh264 error on Slackware current

Well, here are specs which gives you heads up before suggesting ...

bhaskar@Slackware_06:46:54_Sat Nov 20: :~>ffmpeg -codecs | grep h264
ffmpeg version 4.4.1 Copyright (c) 2000-2021 the FFmpeg developers
  built with gcc 11.2.0 (GCC)
  configuration: --prefix=/usr --libdir=/usr/lib64 --shlibdir=/usr/lib64 --docdir=/usr/doc/ffmpeg-4.4.1/html --mandir=/usr/man --disable-debug --enable-shared --disable-static --enable-gpl --enable-version3 --enable-avresample --arch=x86_64 --disable-encoder=aac --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-gnutls --enable-libbluray --enable-libcaca --enable-libcdio --enable-frei0r --enable-openal --enable-libopus --enable-libspeex --enable-libssh --enable-libtheora --enable-libv4l2 --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libmp3lame --enable-opencl --enable-opengl --enable-libopenjpeg --enable-libpulse --enable-libsmbclient --enable-libxml2 --enable-librsvg --enable-libdrm
  libavutil      56. 70.100 / 56. 70.100
  libavcodec     58.134.100 / 58.134.100
  libavformat    58. 76.100 / 58. 76.100
  libavdevice    58. 13.100 / 58. 13.100
  libavfilter     7.110.100 /  7.110.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  9.100 /  5.  9.100
  libswresample   3.  9.100 /  3.  9.100
  libpostproc    55.  9.100 / 55.  9.100
 DEV.LS h264                 H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 (decoders: h264 h264_v4l2m2m ) (encoders: h264_v4l2m2m h264_vaapi )

Also

ffmpeg version 4.4.1 Copyright (c) 2000-2021 the FFmpeg developers
  built with gcc 11.2.0 (GCC)
  configuration: --prefix=/usr --libdir=/usr/lib64 --shlibdir=/usr/lib64 --docdir=/usr/doc/ffmpeg-4.4.1/html --mandir=/usr/man --disable-debug --enable-shared --disable-static --enable-gpl --enable-version3 --enable-avresample --arch=x86_64 --disable-encoder=aac --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-gnutls --enable-libbluray --enable-libcaca --enable-libcdio --enable-frei0r --enable-openal --enable-libopus --enable-libspeex --enable-libssh --enable-libtheora --enable-libv4l2 --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libmp3lame --enable-opencl --enable-opengl --enable-libopenjpeg --enable-libpulse --enable-libsmbclient --enable-libxml2 --enable-librsvg --enable-libdrm
  libavutil      56. 70.100 / 56. 70.100
  libavcodec     58.134.100 / 58.134.100
  libavformat    58. 76.100 / 58. 76.100
  libavdevice    58. 13.100 / 58. 13.100
  libavfilter     7.110.100 /  7.110.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  9.100 /  5.  9.100
  libswresample   3.  9.100 /  3.  9.100
  libpostproc    55.  9.100 / 55.  9.100
Guessed Channel Layout for Input Stream #0.0 : stereo
Input #0, alsa, from 'pulse':
  Duration: N/A, start: 1637371168.782400, bitrate: 1536 kb/s
  Stream #0:0: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
[x11grab @ 0x87db00] Stream #0: not enough frames to estimate rate; consider increasing probesize
Input #1, x11grab, from ':0':
  Duration: N/A, start: 1637371168.825367, bitrate: 839270 kb/s
  Stream #1:0: Video: rawvideo (BGR[0] / 0x524742), bgr0, 1366x768, 839270 kb/s, 25 fps, 1000k tbr, 1000k tbn, 1000k tbc
Unknown encoder 'libx264'

And ..

bhaskar@Slackware_06:50:02_Sat Nov 20: :~>uname -a
Linux Slackware 5.15.1-Slackware #1 SMP Sun Nov 7 10:48:30 IST 2021 x86_64 Intel(R) Core(TM) i5-5200U CPU @ 2.20GHz GenuineIntel GNU/Linux
bhaskar@Slackware_06:50:04_Sat Nov 20: :~>cat /etc/os-release
───────┬──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
       │ File: /etc/os-release
───────┼──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
   1   │ NAME=Slackware
   2   │ VERSION="15.0"
   3   │ ID=slackware
   4   │ VERSION_ID=15.0
   5   │ PRETTY_NAME="Slackware 15.0 x86_64"
   6   │ ANSI_COLOR="0;34"
   7   │ CPE_NAME="cpe:/o:slackware:slackware_linux:15.0"
   8   │ HOME_URL="http://slackware.com/"
   9   │ SUPPORT_URL="http://www.linuxquestions.org/questions/slackware-14/"
  10   │ BUG_REPORT_URL="http://www.linuxquestions.org/questions/slackware-14/"
  11   │ VERSION_CODENAME=stable

Wondering .....when try to build it like mentioned in this place :

https://www.linuxquestions.org/questions/slackware-14/ffmpeg-unknown-encoder-%27libx264%27-4175677695/#post6140669

Am I the only one , who failed to understand ,why the heck is not detecting ??

Also,

root@Slackware_06:52:59_Sat Nov 20:~#ldconfig -p | grep libxh264
root@Slackware_06:53:12_Sat Nov 20:~#ldconfig -p | grep h264
root@Slackware_06:54:18_Sat Nov 20:~#ls /usr/lib64/libxh2*
ls: cannot access '/usr/lib64/libxh2*': No such file or directory
root@Slackware_06:54:46_Sat Nov 20:~#ls /usr/lib/libx2*
ls: cannot access '/usr/lib/libx2*': No such file or directory

Finally....also

bhaskar@Slackware_06:56:58_Sat Nov 20: :~>ffmpeg -encoders | grep h264
ffmpeg version 4.4.1 Copyright (c) 2000-2021 the FFmpeg developers
  built with gcc 11.2.0 (GCC)
  configuration: --prefix=/usr --libdir=/usr/lib64 --shlibdir=/usr/lib64 --docdir=/usr/doc/ffmpeg-4.4.1/html --mandir=/usr/man --disable-debug --enable-shared --disable-static --enable-gpl --enable-version3 --enable-avresample --arch=x86_64 --disable-encoder=aac --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-gnutls --enable-libbluray --enable-libcaca --enable-libcdio --enable-frei0r --enable-openal --enable-libopus --enable-libspeex --enable-libssh --enable-libtheora --enable-libv4l2 --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libmp3lame --enable-opencl --enable-opengl --enable-libopenjpeg --enable-libpulse --enable-libsmbclient --enable-libxml2 --enable-librsvg --enable-libdrm
  libavutil      56. 70.100 / 56. 70.100
  libavcodec     58.134.100 / 58.134.100
  libavformat    58. 76.100 / 58. 76.100
  libavdevice    58. 13.100 / 58. 13.100
  libavfilter     7.110.100 /  7.110.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  9.100 /  5.  9.100
  libswresample   3.  9.100 /  3.  9.100
  libpostproc    55.  9.100 / 55.  9.100
 V..... h264_v4l2m2m         V4L2 mem2mem H.264 encoder wrapper (codec h264)
 V....D h264_vaapi           H.264/AVC (VAAPI) (codec h264)

Greatly appreciated if you come close or pinpoint the reason.

Thanks.